New functions take, drop, {take,drop}-{while,until}.

* lib.c (take_list_fun, take_while_list_fun,
take_until_list_fun): New static functions.
(take, take_while, take_until, drop, drop_while,
drop_until): New functions.

* eval.c (eval_init): Register intrinsics take,
take-while, take-until, drop, drop-while, drop-until.

* txr.1: Documented.

1 files changed, 6 insertions, 0 deletions

diff --git a/eval.c b/eval.c
index 74127bf9..f9a51fed 100644
--- a/eval.c
+++ b/eval.c
@@ -4323,6 +4323,12 @@ void eval_init(void)
   reg_fun(intern(lit("clamp"), user_package), func_n3(clamp));
   reg_fun(intern(lit("pos-max"), user_package), func_n3o(pos_max, 1));
   reg_fun(intern(lit("pos-min"), user_package), func_n3o(pos_min, 1));
+  reg_fun(intern(lit("take"), user_package), func_n2(take));
+  reg_fun(intern(lit("take-while"), user_package), func_n3o(take_while, 2));
+  reg_fun(intern(lit("take-until"), user_package), func_n3o(take_until, 2));
+  reg_fun(intern(lit("drop"), user_package), func_n2(drop));
+  reg_fun(intern(lit("drop-while"), user_package), func_n3o(drop_while, 2));
+  reg_fun(intern(lit("drop-until"), user_package), func_n3o(drop_until, 2));
   reg_fun(intern(lit("in"), user_package), func_n4o(in, 2));
   reg_fun(intern(lit("logand"), user_package), func_n0v(logandv));
   reg_fun(intern(lit("logior"), user_package), func_n0v(logiorv));